The Future of Extra-solar Planetary Exploration
- Finding Jupiters is "easy".
- Finding Earths is 1000 times more
difficult since they have a proportionally smaller influence
on their stars.
- Doppler techniques have been refined so that they are now finding
objects with about 10 times the mass of the Earth (1/30th the mass of Jupiter), but
are still far short of seeing true "Earths".
- Like the goal of sending humans to the Moon in the 1960's, in the 1990's NASA
had set a grand goal of detecting and
imaging other Earth-like planets by the mid-21st century. (Since that time the goal has been replaced by the goal of sending humans to the Moon and Mars.)
- Like the Moon missions, much of the technology is only in the
conceptual phase at present, but there is a clear path to the goal.
- Take a census of the prevalence of other solar systems
around nearby stars -- in progress.
- Detect Earth-sized planets (2010). This work requires either
- Characterize atmospheres and possibly detect life on Earth-sized planets.
- This work requires building
several space telescopes, launching them beyond the orbit
of Jupiter and precisely combining the light they collect -- 2020.
- Main goal: detect oxygen in the atmosphere of
distant earth-like planets.
- Significant oxygen in a planetary atmosphere can be produced and maintained by life. Remove life from the
Earth and the oxygen goes away in a very short time.
- Take a picture of a distant Earth -- 2050?